Field of the Invention
The disclosure generally relates to a transmission line structure, and especially to a transmission line structure for transmitting radio signals.
Description of the Related Art
In order to achieve better area utilization, it is often necessary to cross and interleave various kinds of signal lines. For example, the signal lines could be utilized to transmit many radio signals of a radio frequency, intermediate frequency, and direct current. In order to avoid a short-circuit, which can be caused by interleaving various kinds of signal lines, bond-wiring and back-board wiring are utilized to cross and interleave with the signal lines. However, utilizing the bond-wiring increases costs, and may result in high-frequency effects such as parasitism and coupling, affecting the efficiency of the circuit. In addition, although utilizing the back-board wiring does not increase the cost, the back-board wiring results in high-frequency effects, detracting from the circuit's performance. For example, when grooving the slot and arranging signal lines, the slot will damage the continuity of the ground layer. In addition, wiring between different signal lines will also cause interference for radio signals. Therefore, a transmission line structure is needed to reduce the high-frequency effects without sacrificing circuit performance and increasing the cost.